SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b3f046cf84a4d2458eaf319e34c27d0aa66bd36cb4e19a29511304e4265d0b97' 
  AND token = '+4DVNuR+/gB/zzKPrn6wih3sjWAuJAYlnfzotzecUZA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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