SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '10e2e789703d9d855d10221a23fd880abda98cf284f657356246418f534681df' 
  AND token = '22my1zU8gbUNbn4OuyDOcQfhyqgAozXiqsos+8zeYH8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}