SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'de1442c0c2412beb2febed30579cc9e97007a60d59e2b507c6ad1a1d98028753' 
  AND token = 'uXnd7BJoNV+x9VmlOMTpaAcJbGVkeVmdHLxSXcwmmVo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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