SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fdbf9ba76ad6a9a10e30c13d65f0ea5bd916203a3060ed15bdc40f155732abc0' 
  AND token = 'j+8oKH+GUrp/iWXY3XUbb3BDzOnm8TeVPAUQ2KWYM9w=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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