SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '541f6fef38553a0ac4b7e8c2a26a659c7c4a9aa1f074e9156e4cb2323770a3c6' 
  AND token = 'iDAhR7+5/wCht76awzjjnhsCNp8GgBmqcD6Xzdlovjc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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