SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2b8e7efdb434341432e34d8c6f66deba778a31b8ce79444f16cf88a5092b9f1b' 
  AND token = 'qVFoSZQOyyx8lVU2UhpF2J5AcOSaznGy0SLKfoyquNc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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