SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3439d719dd41d90666b9804707620f4bab548f481ceab6497925e7a397bfd5f3' 
  AND token = '6oBUUrp6sfPlCaEHEmdBu34wfK7QRHmHJiBL+GVQIZc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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