SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b42b6d5179772ae89caa14d5923ae325e7f5ff8834eea7258ffbd1d6c3f0a853' 
  AND token = 'p25VluQqmbHGAuCU+KQsH736yuh0GuBLsrLfdNpmNqg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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