SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '276275eb202c4ffbacf08d3883d356833eba0646bff7470993d32a718520a5cd' 
  AND token = 'hLZLYVwjjhmY7O/j7ik/q1bbDUeoKfOF06YWFiDhTOg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00060

JSON explain

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