SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6779a9a0ea65bf0069c580b067d86df67210f68dcdc87cd642535a045fc13a88' 
  AND token = 'XSIzfVyNanv63sDnKGH6hcBsGlzaFSWpYE/jk2CnUUI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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