SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '202a04bce3bcf64af58a05a256d29fd5e1990199ad7bdaf2ec699cfa8c942f41' 
  AND token = 'FsaBIlj7d2sOt/Gc/iY7g8KFgwuhum8nBz0JTPVla78=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00051

JSON explain

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