SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '178a3d90b13d296dc6fd3ade5ad301615bd06cf6f64dc53862f81aab698877f6' 
  AND token = 'B9pSHsrIIwtnqIKbaDw0R2XX40Qr0VExGqHM5MnQNZo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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