SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd0f65f4d909ac0d6641046592af0934feef8a685d08f5dde6e16b61afc9109f4' 
  AND token = 'vzhnR+RAhoc5/O5IbwdimWmoFB3UwjumdTCF8MEKlKw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00049

JSON explain

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