SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '30ef870677a403f530f83a9d328e586f69b28455f5d835311ebe7716cc971280' 
  AND token = 'BY+CqNBF9t9srUisXKVH3F+au4vfIEV/oLMuvGB0cKY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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