SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '252992868489de36e3b648d240dd39cb68ac11c898ad685057a4b0e09d845642' 
  AND token = 'hlT0bLveIMzpMW1O+sQN6+WBdJbZnhrlnedvR5w/fH4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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