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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a0c8f203c1aca39525f0757e38fd37b2d6ff2d05cb2cd0544e15ee0dd42e679d' 
  AND token = 'Q6b2tUShfCI8JM9P9s4zXlHlqIygA+d+C8RCnRmvb9k=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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