SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8909e92607ebbf4e4facb4489168ce145efad11d9e6346ee2d7bb9baac7e95c2' 
  AND token = 'vwI8Xg46CwzYT3LXpxqqYRv07TWRlSTqCHvImMlAnf0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00059

JSON explain

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