SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '91104acd479d3ddc02d998c37a702f9cffc34e90f194f802c9e37d82be125cf4' 
  AND token = '/3/1i734aQWMx213pxW/+pm0O5aEZ4zo1YItNQxrGZU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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