SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2485343b588eb16f29c586b0943ea413f328d3ef10cd5397597e7bbbf0405548' 
  AND token = 'xONMEKhV+GRgnBTD5wllPv2zPc+jEYhw0LYsX5s/G4A=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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