SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd6a7c51fc7c6890ece4b16353d64759b60461635c780e16ba59fef293d57a458' 
  AND token = 'HpZMUnsnuclSabp4/k0guSuZglVrOdS4Ku6OaV/UcRM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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