SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0cf671a2425b998dbd2db53138df93e96456c7744049c73889acd79534b85cce' 
  AND token = 'ohWGJc7XpBll/FkBygVxD1xqtCRVVob0Sd/DYnbsajM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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