SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2ad7c37dfd12ec88297c277ea9751641bd263fe813bc554213e418759a4f7f36' 
  AND token = 'gdxWBDDeanYfNCbheRW2iY/wQA4zhSHzH2Nbo/uuIQM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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