SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9f5621582935d95a91a088514b712f8233e722ccbcfd30331b32b9181254c2b4' 
  AND token = 'm1ImTQbMoPYJ4+F39XrnkZrL/ppiSkygtcavfRD5Qd4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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