SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'feedc5746361ef480793ebe995b4579738915fb94627fd17b808ac3d76982a2e' 
  AND token = 'qKvNElA030nJpQOOu+0KV4G6Z2iR+DSBY6cuPdeURKM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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