SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0bfcff3a7bde0615698b165445626266a90b851797972acc0cbf12e5361a57c0' 
  AND token = '2ANMoOqWBu9rz1miwh/lIKJkw4GF1/M2DtKLhRHtrP4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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