SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3896942de86f9cc30fc5e1bc34ba78b456e5b6d5b57ab768be90f28d96664727' 
  AND token = 'VTtDLrOG5qYQmo2mRqMGWs0+8gOnLTWd0kF3iCyNXng=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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