SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd57a9cf3e8b8ffbd40b536d370618588457c253e76bf0171876f6f60a674fcf8' 
  AND token = 'PghMcmJySSrADIN0O8PAt0pezRagoc9G3xWOxPtKPsI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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