SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7af6ccea2767deefed49bef014218f361bbfa4d4f9bbe611685771c044236590' 
  AND token = 'hO/IlAa7/+WKe0oOld1uvwyricTUViQtNhA+fx507ZI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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