SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5ab3f06b21925898a5a864ec8dc22d7fe850e6bfb60a95b0c0771d813c55a35e' 
  AND token = 'dLOabU+nnt9qRnvkRkIy8kEAPdN/jvWseGmErRqa5N0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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