SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6cf060b818e3bd41f47793f40e67147e7bf7f6ef76000aab759fa1ed44939535' 
  AND token = 'rrwCbKy/yBtQsatKcKKKGVzAl8oqiLoRp94OG2ykS1g=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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