SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '27108ec921d2ef70efb8cb91fb1410b296b824b4fc5fcb2dbbb89eda7a084d33' 
  AND token = 'W8/FOBIyHudoXQMZwHlxcMDaMrpuOo1r6jBustSZIK8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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