SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '870a25ee87eeee6846c61dce1e4f3c607995f113f15f04b719e2a96a37a9e4e7' 
  AND token = 'W2fXDQQdRcYhVqFDOtMyCzJeOYl542U5jUI9pvEWbks=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}