SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2c246fcc759db2699d69b37a5fe87ff5f33eb52cc350319c92f65f88b590830c' 
  AND token = '3hJLPFI06dpgJ1ZDGOVYLmpWk55JN69RrxrIlQkSG/k=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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