SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '627e605fffbf6ce9e64b2a2da6a9a34147e84595da5a8411f20a1560b98caa13' 
  AND token = 'IYKI/0tXv/FAGNe7fbxcUtzeCs7x4MeU9PNzlsquUg8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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