SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '817208fec7a652ac9085d8aea60a29ba530f837fae414151d962e0caa1228d71' 
  AND token = 'cl5T/QbWxr5ZyyrtAOikPU8donw2ONFgJoO2iFARRDo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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