SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '24ff799b55ef02cba8fc5a8448459ab36141a23e513dcac0210517e698b8af79' 
  AND token = 'V7FbrYDRBe3SjdO1gaCmVYOvdYbrCJm7mVy8DhnAtRM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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