SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8f123d7884f2697593286fe9d2ba7b9e61780f66e6d6484fe02609c4192ed7ab' 
  AND token = 'YSUh1SGZeROLK6tnxN625FSeJCCYGfWTnRuTBGzJzgM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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