SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '458d47cfae0cee94824fbd0b441ad0c7822c55ec46bb2990e268327d4cb9ce72' 
  AND token = 'F6Z1DPKixTm2SNzqvXLmPcSYLr7CVGHAbpa6InDv6Ic=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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