SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '48bc629258e6972a43f5c900efc261522ec93c08799bb16d3aec3b989959d11f' 
  AND token = 'ZAdoH6iAzuN77lwlzNWTVDlB6GjBIeGxhaUajR2ZHrM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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