SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3d2871eb914c1c4c04081de3ef378cdfde725605bc80704d683b562f53783fa4' 
  AND token = 'l6hzbzm2Pgs5KquElLPSLYC/E9DhYRsJoSU/e0cFawI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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