SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '50fbafb5f6e7196c2f5bff7376e78dbc89749e4d6fe1379f26020ac8816322be' 
  AND token = 'BXee30/hSQnoV8TlcrHnDr2qrNq1d+oFzYuc2fOZa6g=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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