SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bfcb4417e0deb6aba68743ef157f78960decafb8110a024891c726b893f82c05' 
  AND token = 'lELQTIdHLEPcnwHZjXxjcVCJZHUujIfz2lPWzLpHLx8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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