SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '91560b37a02b6070e95eb0b1b2e1926c2188e3a8fcd11646bebe91b5cf7eb82b' 
  AND token = 'syNfaZszdW1+vhMDuOWtMEgy5yP+GQRBOTQFI1GAur8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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