SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1f6e2c257832afbcb0a61dfce25db81eedff52401a291a2b08e89cfe408d09f4' 
  AND token = 'yUzVFXuXzTeCnqy0O0DCdgDquXEoR3PR+b8EVwV4kY4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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