SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '67bce93f4650a847a5099835e8a7043867646cafdec2e232397f99de4bf1568b' 
  AND token = 'X6jjLpRKtVJnAw85W2KkzIAfSNRouFkDuJq1v+pGxKE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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