SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7a97be25e429fc57281775e89eb548c1ab11fa82535d652cba9a942fcbecb7d5' 
  AND token = 'GuT4xfqvWAyZ5J0w3AlHLLfv8aEVb3EgdlV2gFhjCkc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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