SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cc44b07c37fd2ed0ff7b2e134fa7813f10b5afba29af758c662b9e522e25c0e5' 
  AND token = '9TbuyrIbauG2JR9lGjHa78LU45UvTbbYvG346w7Fur4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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