SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ce29927a9aa98625fea4e254e511c054d322aec926ae4abda111c9fa11b76f94' 
  AND token = 'Ujp5M6clQTAomozdUP6rL+ntB6cCBvStYJLi4ZvMWwI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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