SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '226cc208790f97fbd52c15d89d8a3be8bb89397b823565fe78f9ebb0f975495a' 
  AND token = 'CSxhMM+kRLgpNCbCwnOc60ghu+7LMWKXjJ2G5ZVYF/I=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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