SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '50950f195e3fcf4596a33bceba4bd9a46872fdb0e4ce7d5924d430c6dd084c56' 
  AND token = 'LVKDPDki7GL95lvHYLFkEBNuCWRBb33BnYLx1yb4KFk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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