SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '244aa3dbdc36b7a30dbc7f12f42965a1eba820051308b132afa551ba4f722732' 
  AND token = 'HA7YPbThgXPgpQ8+v+YBAzKBbuDV39gBGrdmpu4a/0Y=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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