SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3173de9358b3a4355c7f0bc2782cab737b5f12fd86057c5f31870a01e89d3054' 
  AND token = 'Xb8ZWyPNb2yxrXuTtiVgIsTkOWaAjteMLVPSvmejJFQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}