SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e9a78a384049c09f2f76963fd23989b866a23236fd6e882a83c16fce97c392a0' 
  AND token = '5ldrSERZDjz4d8w3SpTWoTE7XvKfnA1RJQPbxsVg6w4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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