SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '78e73d08583dc70d4a38141bb21bb376738a1400d7b3027f522f0c7cd7bde570' 
  AND token = 'Iwu2n0jMhFcBZxOoJHRWvzmdW/bdNYy8P4VmvSAzcXY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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