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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a8d03233777031a33f0ae0db6f72fe085dd0a6f50c893c9bae4d2a81bca23d29' 
  AND token = 'jtRvwJbv5azFrs+HYDetOJqBuE8yj+d5qRCTLY5hRWs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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