SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '409df1f39b76280c1d87e9fc09cbce9cb609837cb236695fa2a889819ff6778b' 
  AND token = 'VqUR5DSuHHp6aEkSNiU49g6oYcmOEP1ObIGJudMPph0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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