SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '634df844364305516fe87dce1f94bbb1c8a95dd24281bb48617131f7e5743439' 
  AND token = 'MpI3omWA//f1URCFITwGchiPoNub9tHEFF7z9+viC2Q=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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