SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bb9bae5a272fc6300c81cb7993b6c16f14ffcdc9b342385a245041891df778c5' 
  AND token = 'ULiinVvELtUe6h1ZLj417fg32r5Fz1fdJuNSHWwJSRY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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