SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '35335eed62ea6819467544226619fc2a471e48c8c24064e7e7e43f95f23fe733' 
  AND token = 'RbGFnFCsLIgXWTZCgvTI3lOw6vylYAnaOzcOSflPMeg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00045

JSON explain

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