SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6b786665a100a6f4d16aadaa5e43fc54416a373335fd213ef98ca0a9194bdcc7' 
  AND token = 'jJWBOGPBvbHhVjsE2r/cfE6S+cBCYHKZj0ftKih6jso=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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