SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5e1d6a51681985eee3926c078237a78b2228dcdca185208f1ead97ddb89406d8' 
  AND token = '37bnzwSNbA3Z8tueSEuGaYLJPS5gJYX2OmxIj2N8S48=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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