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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b4a8fd7db496d9afdcabd7ebf92a58e8b748a6d8a2571220aee977852fec349e' 
  AND token = 'uOCPZvQK8Kl6Ek0rcUAeALu1sWnl6NL/TT4v+fZbKRk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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