SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '88fb7ba06c296d895daff2145fb0529a9c91b594f06b4e434370562393ba5a03' 
  AND token = 'ODfZlKWeL4HHGW1Nh95XhdVdlsex2ZTYzCopnzSrXQw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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