SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '21d41a87a75ca623498dacbb407ae411be9619a1286e4e159dcc9b00e1e24528' 
  AND token = 'HhYpV/XSQwmkR8zNciRMLvSdtPvRMkGbN2aqx2pbhXs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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