SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8d652a5f0d89009de49c248809753f2878df19642c5043e2bf4f3709a84da1be' 
  AND token = 'I0yKldix76i3rPsppx9uOhattaasoFGxDyFBOiCvdsA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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