SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '623c48a862983499e1926ad37e16870f39b61269edf1c8f09dade6ab9dec2328' 
  AND token = 'SHJPXi3K9ejIGJkbhlJ5Dxqr3x1Pd4mxcuUi+Ey6De8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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