SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7aee0f2d04c608c06fde97ce67117387f416f05d2e2d615aa5aa98238243c257' 
  AND token = 'RwHc9jFg3bfnO7bSvSMXJ1PStqy+QZwG2Ll/MeQhWWg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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