SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e0844daf2f9047b1858bd70118970aef737644c332f8415466b67c15622d4a68' 
  AND token = 'mKnG5zFU16KPAVhZPNOo00pQb1OJMdGJpyHqNLipeB4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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