SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bd58226d67f502c3b330e75199480903a48647f25011a28f5a613197a8cb2f35' 
  AND token = 'FUmOAWMYkLV458pS0KrHxh5QOTfqtDH/dowNyu+um6M=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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