SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '73269d23e4e1698363208f3443a4edcaa94dd0d309cf25f3c034d4c70e2bc8ce' 
  AND token = 'RWElpvBE5CK3sKVHUcTxf3dO9jeF5rA68vqjSHtG4GI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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