SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ff123d2b29ac3d871410ad920c21831584ba6a9dd698173dfe58b3e0cc98d772' 
  AND token = 'kH2dPYkZowwiff15k2oGNRQuJIFZroPa6wxf5baTkLM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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