SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '542ff8be877e5afbbdbbe7df162704c52556a9b1de643033ea5f1368729c984e' 
  AND token = 'gJauX+pn/qo1m6FNHBGZxq2kigGCCgpVVKwGAOerAvk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00015

JSON explain

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