SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2db73d54f44326e669923ed9f795678195ca9ec01f2560b00c6bb56a91299d5d' 
  AND token = '17QbypGbBTFfQ0euMF3SutzVSf1zgAZB7dHkSVTbWeI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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