SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c49f9c0d7372f4144bbd04f90f8f2c915104668c851b644ac0b895e066fbc49b' 
  AND token = 'JQBaswTTFz1lFDwUQ75A26ayXKV6l5MlyhxzKdbsMZ0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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