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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e6ace0ade2b8f46cdce7a2e6cbe08398f3f91f5ffe096afc1b6b642d89fc0d54' 
  AND token = 'mbwQFHSApa3i87qTgjJwLPLjnJuaTD+O6PitMj0u+Tc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}