SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '279c45a30d9fd6382ec1072023866b568e913fd230b292f79d928e91a69accbd' 
  AND token = '8WBCcEfRx2WsZcB2x1eyqHemHo3ixT2Niwyy3jNY2MI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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