SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0e446950deb0137d34a3a0f491dc4e9245b7557cf8931d02ab7ae4678c139581' 
  AND token = '78MyGGZBedaxlV34waSrDJaItmoCSaudxcPxaG0BeNY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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