SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5368fa8319fa88d33e4122f12b200b6546693adbc77be315e3917be9882922f7' 
  AND token = '8mSnObUsWpcT5abs7hhfbMsAlCcz2VoRFKf0YD1MV+E=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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