SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'be10d288a358e0942d016a593273d8cab2300ebcbc97929369735acfedebba67' 
  AND token = 'Ww0vXk4d1DMz43JUXgIOC0AEysCJ3dowzTWQHwbWc78=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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