SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '293a12772fea80ca556f09504e0314522f6094d92c0cd4b574ee4f8861520954' 
  AND token = 'KzQ9AJsVUOvTpsS1i283WiF1d1cyiTI/dKdPSRfcODY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00015

JSON explain

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