SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3fbb7c901d9b46aede06d384eca361c93eb28bc038584c8dff6756d38d5423f7' 
  AND token = 'tiEWHs+pjbCZdpgFDpzUlq+etYd8rWM7TAmAEBTVcjc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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