SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b80f7ca9f8c826cb83da16be00977463827870067bf8f2faeba6626513dc8e72' 
  AND token = 'dmU6egBKSjbuGoxaQBWGWdX2aPpFMkHpPD64gGYHKcc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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