SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9a2816179579ef866fe781e9d5813d3d40c2d2a8b2d527db6b20c13608807835' 
  AND token = 'dCihUi05fTBy8404HevhQKpVbBLNFj9j0xbgzVI3Dm8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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