SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd915cf2bb356ec0e94b8764cda359b611924e1f46a409f0d6c543094e58ae842' 
  AND token = 'clcYwiPyBCtxooXPjVPRMRzcPh8Dwv1X2FBy4Hdq41o=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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