SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '18c0406570f16c1c9b0887e20554a58ebc254ef050c1b3849a35ffd83d485e61' 
  AND token = 'eGlii8bim5TmV2ZeCAl/cmyMdWJRKIamtacJX0OLTMc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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